Describe a community interaction that you see evidence of (either direct or indirect). These can be: (predator-prey relationships, symbioses, competition, invasive species, etc)

symbioses might occur between the different types of fish....some might be bottom feeders while others aren't so both benefit
While at the same time they might have to compete for food due to the high amount of fish in the pond
There might be an invasive species such as a particular type of algae